Glioblastoma Multiforme

glioblastoma multiforme

This 65 year-old patient presented with weakness of the right leg. This coronal T1-weighted gadolinium-enhanced MR image shows a rim-enhancing lesion in the left frontoparietal region. The area of contrast enhancement extends to the pial surface. There is surrounding white matter low signal consistent with vasogenic oedema. There was no restricted diffusion within the lesion, making cerebral abscess less likely. The main differential diagnoses entertained on imaging findings were solitary metastasis, or primary cerebral tumour such as astrocytoma.

A craniotomy and excision biopsy was performed. The histological features were marked hypercellularity, nuclear pleomorphism, high mitotic rate, palisading, ischaemic necrosis and microvascular proliferation – glioblastoma multiforme (WHO Grade IV astrocytoma).

GBM is an aggressive astrocytic tumour characterised by necrosis and neovascularity. It may arise de novo (primary) or from degeneration of lower grade astrocytoma (secondary). The peak age range is 45-70. GBM typically extends along white matter tracts and may cross the corpus callosum. An irregular enhancing rim surrounding a necrotic core is typical, and high T2 signal often extends far beyond the zone of enhancement. Viable tumour may extend beyond even the T2 changes. Diffusion-weighted imaging may help to differentiate from abscess (restricted diffusion typical in abcess).

References:
1. STATdx, Amirsys
2. JH Rees et al. Glioblastoma multiforme: radiologic-pathologic correlation. RadioGraphics, Vol 16, 1413-1438, 1996

Credit: Dr Laughlin Dawes, Dr Jason Wenderoth